The paradox of tolerance states that if a society is tolerant without limit, its ability to be tolerant is eventually ceased or destroyed by the intolerant. Karl Popper described it as the seemingly self-contradictory idea that in order to maintain a tolerant society, the society must retain the right to be intolerant of intolerance. Popper specified that the intolerance not to be tolerated involves the refusal to engage in "rational argument".
Discussions
In 1945, philosopher Karl Popper attributed the paradox to Plato's defense of "benevolent despotism" and defined it in The Open Society and Its Enemies.
The term "paradox of tolerance" does not appear anywhere in the main text of The Open Society and Its Enemies. Rather, Popper lists the above as a note to chapter 7, among the mentioned paradoxes proposed in Plato's apologia for "benevolent despotism"—i.e., true tolerance would inevitably lead to intolerance, so autocratic rule of an enlightened "philosopher-king" would be preferable to leaving the question of tolerance up to majority rule. In the context of chapter 7 of Popper's work, specifically, section II, the note on the paradox of tolerance is intended as further explanation of Popper's rebuttal specific to the paradox as a rationale for autocracy: why political institutions within liberal democracies are preferable to Plato's vision of despotism, and through such institutions, the paradox can be avoided. The chapter in question explicitly defines the context to that of political institutions and the democratic process, and rejects the notion of "the will of the people" having valid meaning outside of those institutions. Thus, in context, Popper's acquiescence to suppression when all else has failed applies only to the state in a liberal democracy with a constitutional rule of law that must be just in its foundations, but will necessarily be imperfect.
Thomas Jefferson addressed the notion of a tolerant society in his first inaugural speech as President of the United States, concerning those who might destabilize the United States and its unity, saying, "let them stand undisturbed as monuments of the safety with which error of opinion may be tolerated where reason is left free to combat it."
In 1971, philosopher John Rawls concluded in A Theory of Justice that a just society must tolerate the intolerant, for otherwise, the society would then itself be intolerant, and thus unjust. However, Rawls qualifies this with the assertion that under extraordinary circumstances in which constitutional safeguards do not suffice to ensure the security of the tolerant and the institutions of liberty, tolerant society has a reasonable right of self-preservation against acts of intolerance that would limit the liberty of others under a just constitution, and this supersedes the principle of tolerance. This should be done, however, only to preserve equal liberty i.e., the liberties of the intolerant should be limited only insofar as they demonstrably limit the liberties of others: "While an intolerant sect does not itself have title to complain of intolerance, its freedom should be restricted only when the tolerant sincerely and with reason believe that their own security and that of the institutions of liberty are in danger."
In On Toleration (1997), Michael Walzer asked, "Should we tolerate the intolerant?" He claims that most minority religious groups who are the beneficiaries of tolerance are themselves intolerant, at least in some respects. In a tolerant regime, such (intolerant) people may learn to tolerate, or at least to behave "as if they possessed this virtue".